Display apparatus and touch detection apparatus using shift of detection operation for reduced detection time

ABSTRACT

A display apparatus includes: a display face; a display function layer adapted to vary display on the display face in response to an inputted image signal; a plurality of driving electrodes disposed separately in one direction; a detection scanning control section configured to apply a detection driving voltage to some of the plural driving electrodes and carry out detection driving scanning while shifting an application object of the detection driving voltage in the one direction on the display face and then control the detection driving scanning such that jump shift of carrying out shift with a pitch of twice or more times a driving electrode pitch is included; and a plurality of sensor lines disposed separately in a direction different from the one direction and responding to touch or proximity of a detection object with or to the display face to exhibit an electric variation.

The present application is a continuation of application Ser. No.15/068,614 filed on Mar. 13, 2016, which is incorporated herein byreference. Application Ser. No. 15/068,614 is a Continuation ofapplication Ser. No. 12/776,233, filed May 7, 2010, now U.S. Pat. No.9,298,294, issued Mar. 29, 2016, which claims priority to JapanesePatent Application JP 2009-120614 filed on May 19, 2009, and JapanesePriority Patent Application JP 2010-063024 filed in the Japanese PatentOffice on Mar. 18, 2010, the entire contents of which are herebyincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display apparatus having a functionfor detecting touch or proximity of a finger, a pen or the like with orto a detection face by the user, that is, a function of touch detectionsuch as a touch panel or a like apparatus. The present invention furtherrelates to a touch detection apparatus having the touch detectionfunction.

2. Description of the Related Art

For a touch detection method for a touch panel, three types including anoptical type, a resistance film type and a capacitance type are known.

Meanwhile, in order to associate electrical variation occurring inresponse to touch or proximity with position information, a great numberof wiring lines combined so as to be capable of achieving positionspecification and arranged in a matrix are required. According to amethod of position detection which depends upon a combination of wiringlines, a great number of wiring lines are required to increase theresolution of the detection.

Therefore, in the three detection methods, a driving method fordetecting a touch position or a proximity position while a line fromwhich an electric variation is to be outputted is scanned in onedirection is becoming the mainstream. For example, a driving method ofthe optical type is disclosed in Hirotaka Hayashi etc. “Optical SensorEmbedded Input Display Usable under High-Ambient-Light Conditions,” SID07 DIGEST, p. 1105 (hereinafter referred to as Non-Patent Document 1).Meanwhile, a driving method of the resistance film type is disclosed inBong Hyun You etc., “12.1-inch a-Si:H TFT LCD with Embedded Touch ScreenPanel,” SID 08 DIGEST p. 830 (hereinafter referred to as Non-PatentDocument 2). Further, a driving method of the capacitance type isdisclosed in Joohyung Lee etc., “Hybrid Touch Screen Panel Integrated inTFT-LCD,” SID 08 DIGEST p. 834 (hereinafter referred to as Non-PatentDocument 3). Here, the term “line” signifies an array in an X directionor a Y direction of fine sensor sections arranged two-dimensionally inaccordance with a predetermined rule for touch detection.

Incidentally, if a touch panel is provided in an overlappingrelationship on a display panel, then the thickness of the overalldisplaying module increases. Further, a retaining member for retainingthe touch panel on the display panel is required, and the area of aframe (portion around an effective detection face) increases and thecost increases.

Therefore, in recent years, the mainstream of the type to be developedhas changed from a type wherein a touch panel is mounted in anoverlapping relationship on a display panel to another type wherein atouch panel is built in a display panel (refer to Non-Patent Documents 1to 3 and Japanese Patent Laid-Open No. 2008-9750 (hereinafter referredto as Patent Document 1)).

In the following description, “display apparatus with touch sensor” isused as a denomination of an apparatus which has any form ofincorporation of a touch panel in regard to whether the touch panel ismounted in an overlapping relationship on a display panel or is formedintegrally with a display panel.

SUMMARY OF THE INVENTION

A user of a touch panel sometimes feels delay after the user touches adetection face until the touch is detected. If the delay is long, thenthis degrades the operability. Further, depending upon applicationsoftware, it is required to minimize the delay. The delay time after anexecution instruction is issued until execution of the instruction iscompleted is called latency, and in order to improve the operability,improvement in regard to the latency is required.

Therefore, as a driving method for achieving improvement in regard tothe latency, it seems a possible idea that, where a touch detectionapparatus is driven for each line, lines along one or both of a Y-axialdirection and an X-axial direction are voltage-driven ordetection-scanned successively at a high speed.

However, if the driving frequency or the like upon detection scanning isincreased to raise the speed of the detection scanning in the touchdetection apparatus, then power consumption increases. Further, if thedriving frequency or the like upon detection scanning is increased wherethe time constant of a wiring line or the like is high, then theamplitude of a detection signal decreases and the detection accuracysometimes degrades.

The present invention provides a display apparatus having a function oftouch detection wherein the latency is reduced and the responsibility isimproved without increasing the detection driving frequency. Further,the present invention provides a touch detection apparatus having afunction of the touch detection.

According to an embodiment of the present invention, there is provided adisplay apparatus including: a display face; a display function layeradapted to vary display on the display face in response to an inputtedimage signal; a plurality of driving electrodes disposed separately inone direction; a detection scanning control section configured to applya detection driving voltage to some of the plural driving electrodes andcarry out detection driving scanning while shifting an applicationobject of the detection driving voltage in the one direction on thedisplay face and then control the detection driving scanning such thatjump shift of carrying out shift with a pitch of twice or more times adriving electrode pitch is included; and a plurality of sensor linesdisposed separately in a direction different from the one direction andresponding to touch or proximity of a detection object with or to thedisplay face to exhibit an electric variation.

In the display apparatus, in the detection driving scanning which isexecuted and controlled by the detection scanning control section, theshift which is repeated by a plural number of times within a scanningperiod of the display face includes the jump shift. Therefore, as thefrequency of the jump shift increases, the time before touch is detectedfirst on the display face within the period of detection scanningbecomes short. It is to be noted that, where the term “touch detection”is used herein, not only it is detected that a detection object toucheswith the display face but also it is detected that a detection object ispositioned in the proximity of the display face.

Where sequential scanning from one side to the other side of the pluraldriving electrodes in the separation direction, that is, in the onedirection without applying the present invention, that is, withoutinvolving the jump shift, the response of touch detection where adetection object exists on the far side from the scanning start point islater than the response of touch detection where a detection objectexists on the near side to the scanning start point.

In contrast, with the display apparatus according to the embodiment ofthe present invention, touch detection in the detection face can becarried out roughly only by repeating the jump shift several times.Therefore, where it is desired to detect presence or absence of adetection object rapidly, even if the frequency of the detection drivingscanning is equal, the interval until touch is detected first isshortened by such jump shift.

According to another embodiment of the present invention, there isprovided a touch detection apparatus including: a detection face; aplurality of driving electrodes disposed separately in one direction; adetection scanning control section configured to apply a detectiondriving voltage to some of the plural driving electrodes and carry outdetection driving scanning while shifting an application object of thedetection driving voltage in the one direction on the detection face andthen control the detection driving scanning such that jump shift ofcarrying out shift with a pitch of twice or more times a drivingelectrode pitch is included; and a plurality of sensor lines disposedseparately in a direction different from the one direction and adaptedto exhibit, if a detection object is brought into touch with orproximity to the detection face while the detection driving scanning isbeing carried out by the detection scanning control section, electricvariation in response to the touch or the proximity.

Different from the display apparatus described above, the touchdetection apparatus does not have the display function layer.

Where the touch detection apparatus is applied to a liquid crystaldisplay apparatus, a liquid crystal layer corresponds to the displayfunction layer described above. Further, where the touch detectionapparatus is applied to a liquid crystal display apparatus or a likedisplay apparatus, two electrodes such as a pixel electrode and adriving electrode for applying a display voltage to each pixel of thedisplay function layer, that is, the liquid crystal layer, may bedisposed such that they sandwich the liquid crystal therebetween or maybe disposed on the side remote from the display face.

For example, in order to reduce the thickness of the entire displayapparatus, the plural driving electrodes for the detection drivingscanning preferably serve also as display driving electrodes for displaydriving scanning.

In this instance, in the liquid crystal display apparatus, the detectionscanning control section and the display scanning control section may beformed as separate circuits from each other or may be formed as a singlecircuit.

In summary, with the display apparatus and the touch detectionapparatus, the latency can be reduced to improve the responsibilitywithout raising the detection driving frequency.

The above and other features and advantages of the present inventionwill become apparent from the following description and the appendedclaims, taken in conjunction with the accompanying drawings in whichlike parts or elements denoted by like reference symbols.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are an equivalent circuit diagram and a schematicsectional view, respectively, illustrating operation of a touch sensorsection according to first and second embodiments;

FIGS. 2A and 2B are an equivalent circuit diagram and a schematicsectional view, respectively, where a finger is in touch with orproximate to the touch sensor section shown in FIGS. 1A and 1B;

FIGS. 3A to 3C are diagrams illustrating input and output waveforms ofthe touch sensor section according to the first and second embodiments;

FIGS. 4A and 4B are a top plan view and a schematic sectional view,respectively, showing a configuration of a touch detection apparatusaccording to the first embodiment;

FIGS. 5A to 5C are a top plan view, an equivalent circuit diagram and anexpression, respectively, illustrating touch sensor detection accordingto the first embodiment;

FIGS. 6A to 6C are top plan views and FIG. 6D is a schematic sectionalview illustrating a connection scheme between an electrode pattern fortouch detection and a driving circuit of the display apparatus accordingto the second embodiment;

FIG. 7 is an equivalent circuit diagram of a pixel circuit of thedisplay apparatus according to the second embodiment;

FIG. 8 is a circuit diagram showing an example of a circuit of a touchdetection section of the display apparatus according to the secondembodiment;

FIG. 9 is a schematic sectional view of a liquid crystal displayapparatus of a lateral field mode according to the second embodiment;

FIGS. 10A and 10B are diagrammatic views of a first example of shiftoperation;

FIGS. 11A and 11B are diagrammatic views of a second example of shiftoperation;

FIGS. 12A and 12B are diagrammatic views of a third example of shiftoperation;

FIGS. 13A and 13B are diagrammatic views of a fourth example of shiftoperation;

FIGS. 14A and 14B are diagrammatic views of a fifth example of shiftoperation;

FIGS. 15A and 15B are diagrammatic views of a sixth example of shiftoperation;

FIGS. 16A and 16B are diagrammatic views of a seventh example of shiftoperation;

FIGS. 17A and 17B are diagrammatic views of an eighth example of shiftoperation;

FIG. 18 is a schematic block diagram of the display apparatus showing afirst example of a configuration of a scanning driving section;

FIG. 19 is a schematic block diagram of the display apparatus showing asecond example of a configuration of a scanning driving section;

FIGS. 20A and 20B are perspective views showing a digital still cameraincluding the liquid crystal display apparatus to which an embodiment ofthe present invention is applied;

FIG. 21 is perspective view showing a notebook type personal computerincluding the liquid crystal display apparatus to which an embodiment ofthe present invention is applied;

FIG. 22 is a perspective view showing a video camera including theliquid crystal display apparatus to which an embodiment of the presentinvention is applied; and

FIGS. 23A and 23B are front elevational views showing a portableterminal apparatus including the liquid crystal display apparatus towhich an embodiment of the present invention is applied in an open stateand a closed state, respectively.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, embodiments of the present invention are describedtaking a capacitance type touch detection apparatus and a liquid crystaldisplay apparatus having a function for touch detection as principalexamples with reference to the drawings. It is to be noted that thepresent invention can be applied also to a resistance film typeapparatus and an optical type apparatus. Further, while a liquid crystaldisplay apparatus is taken as an example here, the present invention canbe applied also to a different display apparatus such as an organic ELdisplay apparatus or the like.

Description is given in the following order.

1. First Embodiment: Touch Detection Apparatus

2. Second Embodiment: Liquid Crystal Display Apparatus

3. Modifications

4. Applications to Electronic Apparatus

1. First Embodiment Basic Configuration and Operation of Touch Detection

First, as a matter which is a prerequisite to the first embodiment butis common to the other embodiment, a basis of capacitance type touchdetection is described with reference to FIGS. 1A to 3C.

FIGS. 1A and 2A are equivalent circuit diagrams of a touch sensorsection and FIGS. 1B and 2B are structure views (schematic sectionalviews) of the touch sensor section. Here, FIGS. 1A and 1B show a casewherein a finger as a detection target is not proximate to a sensor andFIGS. 2A and 2B show another case wherein the finger touches with orapproaches the sensor.

The touch sensor section shown in FIGS. 1A and 2A is a capacitance typetouch sensor and is formed from a capacitance element as shown in FIGS.1B and 2B. In particular, a capacitance element (capacitance) C1 isformed from a dielectric D and a pair of electrodes disposed in anopposing relationship in such a manner as to sandwich the dielectric Dtherebetween, that is, a driving electrode E1 and a detection electrodeE2.

As shown in FIGS. 1A and 2A, the driving electrode E1 of the capacitanceelement C1 is connected to an AC signal source AS for generating an ACpulse signal Sg. The detection electrode E2 of the capacitance elementC1 is connected to a detection circuit DET. The detection electrode E2is grounded through a resister R so that the DC level is electricallyfixed. It is to be noted that such grounding through the resister is notessentially required, and, for example, through a logic circuit, thedetection electrode E2 may be fixed to the GND potential or a differentpotential within a certain period and may be in a floating state withinanother certain period.

An AC pulse signal Sg having a predetermined frequency, for example, anapproximately several [kHz] to several tens [kHz], is applied from theAC signal source AS to the driving electrode E1.

A waveform diagram of the AC pulse signal Sg is shown in FIG. 3B. Asignal having an output waveform shown in FIG. 3A, that is, a detectionsignal Vdet, appears on the detection electrode E2 in response toapplication of the AC pulse signal Sg.

It is to be noted that, while details are described in connection withthe second embodiment of the present invention hereinafter described, inthe liquid crystal display apparatus which has a function of a touchdetection apparatus in a liquid crystal display panel therein, a drivingelectrode E1 corresponds to an opposing electrode for liquid crystaldriving, that is, to an electrode which is disposed in an opposingrelationship and commonly to a plurality of pixels. Here, since theopposing electrode undergoes AC driving called Vcom driving in order todrive the liquid crystal. Therefore, in the second embodimenthereinafter described, a common driving signal for the Vcom driving isused also as an AC pulse signal Sg for driving the driving electrode E1for a touch sensor.

In a state illustrated in FIGS. 1A and 1B wherein a finger does nottouch the touch detection apparatus, the driving electrode E1 of thecapacitance element C1 is AC driven, and an AC detection signal Vdetappears on the detection electrode E2 in response to charging anddischarging of the capacitance element C1. The detection signal at thistime is hereinafter referred to as “initial detection signal Vdet0.”Since the detection electrode E2 side is not grounded in a highfrequency although it is DC grounded, it does not have an AC dischargingpath and the pulse peak value of the initial detection signal Vdet0 iscomparatively high. However, if time passes after the AC pulse signal Sgrises, then the pulse peak value of the initial detection signal Vdet0gradually drops due to loss.

FIG. 3C illustrates a waveform in an enlarged scale together with ascale. Referring to FIG. 3C, the pulse peak value of the initialdetection signal Vdet0 exhibits a drop by approximately 0.5 V from itsinitial value of 2.8 V by lapse of a short period of time due to highfrequency loss.

If, in this initial state, a finger is brought into touch with thedetection electrode E2 or comes to a very short distance to thedetection electrode E2 at which it has an influence on the detectionelectrode E2, then the circuit state varies to a state equivalent tothat in a case wherein a capacitance element C2 is connected to thedetection electrode E2 as seen in FIG. 2A. This is because the humanbody is equivalent in terms of a high frequency to a capacitor which isgrounded on one side thereof.

In this touching state, a discharge path of an AC signal through thecapacitance elements C1 and C2 is formed. Consequently, in response tocharging and discharging of the capacitance elements C1 and C2, ACcurrent I1 and I2 flows through the capacitance elements C1 and C2,respectively. Therefore, the initial detection signal Vdet0 is dividedinto values which depend upon the ratio of the capacitance elements C1and C2 and so forth, and the pulse peak value drops.

A detection signal Vdet1 illustrated in FIGS. 3A and 3C appears with thedetection electrode E2 when a finger touches the touch detectionapparatus. From FIG. 3C, it can be recognized that the dropping amountof the detection signal is approximately 0.5 to 0.8 V. A detectioncircuit DET shown in FIGS. 1A to 2B detects the drop of the detectionsignal using, for example, a threshold value Vt to detect the touch of afinger.

General Configuration of the Touch Detection Apparatus

FIG. 4A shows a schematic plan view of the touch detection apparatusaccording an embodiment of the present invention. In the plan view, aprotective layer of the outermost surface is omitted such that theinside of the apparatus is observed through a detection face, that is,the outermost face of the protective layer. Meanwhile, FIG. 4B shows aschematic sectional view taken along line A-A of FIG. 4A.

As seen in FIG. 4B, the touch detection apparatus 10 includes a firstsubstrate 11, a second substrate 12, and a driving electrode DEmdisposed between the first substrate 11 and the second substrate 12. Thesecond substrate 12 has n sensor lines SL1 to SLn disposed on a facethereof remote from the driving electrode DEm, that is, on a facethereof on the detection face side.

The n sensor lines SL1 to SLn are formed as wiring lines elongated in ay direction as seen in FIG. 4A. An arbitrary one of the sensor lines SL1to SLn is hereinafter referred to as sensor line SLi (i=1, 2, 3, . . . ,n).

The number of such driving electrodes is m, and the m driving electrodesare formed as belts elongated in an x direction and disposed at an equalpitch in the y direction. The m driving electrodes DEj (j=1, 2, 3, . . ., m) are disposed in a direction different from that of the n sensorlines SL1 to SLn. In the present example, the driving electrodes DEj andthe sensor lines SLi are disposed orthogonally to each other.

The material of the first substrate 11 and the second substrate 12 shownin FIG. 4B is not limited particularly. However, it is necessary for thesensor lines SLi of the n sensor lines SL1 to SLn to be capacitivelycoupled to individual ones DEj of the m driving electrodes DE1 to DEm.Therefore, the thickness and the material of the second substrate 12 aredetermined from a point of view that the capacitive coupling should havea predetermined strength. From this point of view, some insulator may beinterposed between the n sensor lines SL1 to SLn and the m drivingelectrodes DE1 to DEm.

Referring to FIG. 4A, a scanning driving section 9 is disposed such thatit is connected to one end of the m driving electrodes DE1 to DEm.Further, a touch detection section 8 is disposed such that it isconnected to one end of the n sensor lines SL1 to SLn.

The scanning driving section 9 has an AC signal source AS for eachdriving electrode as seen in FIGS. 1A to 2B. The scanning drivingsection 9 changes over that one of the AC signal sources AS which is tobe activated in a direction indicated by an arrow mark, that is, in ascanning direction, within the block of the scanning driving section 9of FIG. 4A. Or, the scanning driving section 9 has a single AC signalsource AS and changes over connection between the single AC signalsource AS and one of the m driving electrodes DEj in the scanningdirection.

The scanning driving section 9 corresponds to one example of a“detection scanning control section” which carries out detection drivingscanning. The “detection driving scanning” here signifies operation ofrepeating application of a detection driving voltage such as, forexample, an AC voltage and shifting the application object in onedirection by a plural number of times within a scanning period withinthe detection face.

Generally, where the term “scanning” is used, it frequently signifiesoperation of changing over a driving electrode of a voltage applicationobject to which a driving voltage, which is not limited to an AC voltageand a DC voltage, is to be actually applied successively from a one-endone to the other-end one of the m driving electrodes.

However, although, in the present invention, sequential scanning, whichis scanning of changing over the driving electrode DE as a voltageapplication object from a start point to an end point of the arrow mark,is not always carried out, sequential scanning may be carried outpartially. This is because a jump shift of shifting a voltageapplication object jumping over some driving electrodes DE is carriedout midway. Further, the scanning driving section 9 sometimes carriesout scanning different from the sequential scanning such as sequentialscanning in the opposite direction to the direction of the arrow mark orscanning which includes a jump shift in the opposite direction to thedirection of the arrow mark. It is to be noted that the directionindicated by the arrow mark in the scanning driving section 9 of FIG. 4Amerely indicates a direction of basic scanning carried out by thescanning driving section 9.

From the foregoing, it can be considered that the scanning drivingsection 9, that is, the detection scanning control section, is a circuitwhich controls the shift of a voltage application object such that ajump shift of carrying out detection driving scanning in a pitch equalto twice or more of the pitch of the driving electrodes is included.

The scanning driving section 9 should be controlled in terms of itsscanning algorithm, particularly in the manner of a shift, based on acontrol signal provided thereto from the outside such as, for example, aCPU (Central Processing Unit) or a pulse generation circuit not shown. Aparticular block configuration of the scanning driving section 9 ishereinafter described.

Further, as described in connection with modifications hereinafterdescribed, the scanning algorithm may include an algorithm for voltageapplication such as control of the magnitude or phase of the voltage tobe applied in addition to the manner of shift operation.

It is to be noted that, in the present embodiment, the orthogonalarrangement of the driving electrodes and the sensor lines is notessentially required, and if the capacitive coupling between the sensorlines and the driving electrodes is uniform or substantially uniform inthe detection plane, then there is no necessity to particularly limitingthe shape or arrangement of the sensor lines and the driving electrodes.

However, if the sensor lines are led out from one of two orthogonalsides of the detection face and connected to the touch detection section8 while the driving electrodes are led out from the other one of the twosides and connected to the scanning driving section 9 as seen in FIG.4A, then it is easy to arrange the touch detection section 8 and thescanning driving section 9. Therefore, although the orthogonalarrangement of the driving electrodes and the sensor lines ispreferable, this is not essentially required.

Algorithm of Shift Operation

Here, an outline of a shift algorithm is described.

A shift executed by application of an embodiment of the presentinvention can be carried out roughly in two different manners includinga manner wherein it is carried out at random and another manner whereinit is carried out regularly.

A random shift is executed such that the shift amount or the shiftdirection, that is, selection of a voltage application object, for anext shift is determined every time using, for example, a random numbergenerated by the scanning driving section 9 itself or a random numbersupplied from the outside. The random shift “controls, where shiftoperation is to be carried out by an amount equal to P (≥1) times thedriving electrode pitch, the value of P.” Since the random shift iscarried out at random, naturally it includes a jump shift at a highprobability.

As a result where a random shift is carried out, the probability thatsequential scanning may be carried out is minimized but is not zero.Particularly where only several driving electrodes DE are involved, sucha probability that jump scanning is not carried out at all cannot beignored.

However, since usually the number m of driving electrodes DE is as greatas several hundreds, where a random shift is carried out, theprobability that jump scanning may not be carried out at all within ascanning period of time of one screen may be regarded as being zero.Conversely speaking, where a random shift is carried out, it isnecessary for the number m of driving electrodes DE to be so great thata jump shift is included one time or more within a scanning period oftime of one screen. Here, the “scanning period of time of one screen” isa period of time, in the case of sequential scanning, from the start ofdriving of the first driving electrode DE1 to the end of the driving ofthe last driving electrode DEm.

On the other hand, in regard to a periodical shift, the algorithmtherefor should be determined such that a jump shift is included onetime or more within a scanning period of time of one screen. However,since the object of a jump shift is to recognize touch detection asearly as possible, it is necessary to set the shift value of a jumpshift, that is, the driving electrode pitch P upon a jump shift, to asomewhat high value. To this end, regular shift operation preferably isshift operation which is carried out, when one screen is partitionedinto F (≥2) regions in the y direction, as uniformly as possible betweenthe regions. At this time, preferably the shift operation is carried outfor movement of a driving object between the regions.

Or, a jump shift is preferably carried out continually by a small jumpamount, that is, by a plurality of pixel electrode distances, forexample, by a pitch of one to three or four pixel electrodes. Althoughthis technique can be regarded as sequential scanning by a finer pitchthan that of display scanning, while the driving frequency is equal tothat upon display, the scanning time between the opposite ends of thescreen is shorter than that upon display. As a result, this technique isa technique of “carrying out detection driving scanning for N+1 screenswithin a period of display driving scanning for N screens.”

An example of operation of a shift of movement of a driving objectbetween regions and an example of a continual jump shift are hereinafterdescribed in connection of the other embodiment. It is to be noted thatalso it is possible to use a combination of regular shift operation andrandom shift operation such that only the regularity of operation of ashift of movement of a driving object between regions is determined byan algorithm and randomness is applied to a procedure for selection of adriving electrode DE in each region.

Incidentally, while detection driving scanning carried out by thescanning driving section 9 is repetitions of application of a detectiondriving voltage such as, for example, an AC voltage and shift operation,the two operations are preferably carried out as one cycle in a fixedperiod. This is because this makes it easy for the touch detectionsection 8 to decide a timing of detection of presence or absence oftouch.

In this instance, the scanning driving section 9, that is, the detectionscanning control section, may execute and control halting of driving formore than one cycle within which application of the detection drivingvoltage is not carried out although the shift is carried out or neithershift nor application of the voltage is carried out periodically or fora certain region.

Particularly in continual jump shift, in order to scan a next screenafter rough sequential scanning is carried out from one end to the otherend of a screen image, a fly-back period within which the scanningposition returns to the first scanning start position and/or a fixedperiod after the fly-back may be used as the period for halting ofdriving.

Meanwhile, the touch detection section 8 may be configured such that itincludes a noise removing section which detects, within the drivinghalting period, a noise level from the potential level of the sensorline SLi on which an electric variation is not overlapped and whichbecomes a detection signal and carries out noise removal. The provisionof the noise removing section in the touch detection section 8 is notessentially required, but also it is possible to carry out noise removalby means of a circuit different from the touch detection section 8.

Further, while, in FIG. 4A, the touch detection section 8 is provided inthe touch detection apparatus 10, also this itself is not necessarilyrequired. The touch detection apparatus 10 may output n sensor lineoutputs to the outside such that touch detection is carried out outsidethe touch detection apparatus 10.

This similarly applies also to the display apparatus according to thesecond embodiment hereinafter described. In other words, a configurationsimilar to the touch detection section 8 may be provided outside adisplay apparatus.

A signal component and a noise component of the sensor line SL1 arehereinafter described.

Detection Signal

FIG. 5A illustrates a manner wherein an AC signal source AS drives thefirst driving electrode DE1 from among the m driving electrodes DE1 toDEm. Meanwhile, FIG. 5B shows an equivalent circuit of the touch sensorwhere a finger of a user is proximate to an arbitrary one of the nsensors shown in FIG. 5A, that is, a sensor line SLi.

As shown in FIG. 5A, the AC signal source AS is connected to the drivingelectrode DE1 so that the driving electrode DE1 is AC driven. At thistime, the touch sensor is represented by such an equivalent circuit asshown in FIG. 5B. However, it is to be noted here that the capacitancevalue of each of the capacitance elements C1_1 to C1_m is represented by“Cp” and a capacitance component connected to the sensor line SLi otherthan the capacitance elements C1_1 to C1_m, that is, a parasiticcapacitance, is represented by “Cc.” Further, the effective value of theAC voltage from the AC signal source AS is represented by “V1.” At thistime, the detection signal Vdet detected by the touch detection section8 (refer to FIG. 4A) exhibits a voltage Vs when no finger touches but isanother voltage Vf (<Vs) when a finger touches. In a relationship toFIGS. 3A to 3C, the voltage Vs corresponds to the “initial detectionsignal Vdet0” and the voltage Vf corresponds to the “detection signalVdet1.” Voltages Vs, Vf are hereinafter referred to as sensor voltages.

The sensor voltage Vs when no finger touches is represented by such anexpression as given in FIG. 5C. From this expression, as the number m ofthe driving electrodes DE increases, each capacitance value Cp decreasesas much. Therefore, “mCp” in the denominator of the expression of FIG.5C becomes substantially fixed. Further, although the value of theparasitic capacitance Cc is influenced a little by the number m of thedriving electrodes DE, it may be regarded as being substantially fixed.Therefore, although the denominator of the expression of FIG. 5C doesnot exhibit a great variation, the numerator becomes small. Therefore,as the number m of the driving electrodes DE increases, also themagnitude of the sensor voltage Vs, that is, the peak value of thedetection signal when no finger touches, decreases. On the other hand,the sensor voltage Vf, that is, the peak value of the detection signalwhen a finger touches, increases substantially in inverse proportion to“mCp” but increases substantially in proportion to “Cp” similarly to thesensor voltage Vs. This is because the value of the capacitance elementC2 added by proximity of a finger is sufficiently lower than thecapacitance value Cp.

From the foregoing, as the number m of the driving electrodes DEincreases, the peak value of the detection signal decreases.

In contrast, if the number m of the driving electrodes DE is small andthe area of the one driving electrode DE1 is large, then although thepeak value of the detection signal increases, the resolution, whichcorresponds to the size of a minimum detection object which can bedetected, when the size of a detection object is detected, decreases.Further, in the case of position detection of a detection object, alsothe accuracy in position detection decreases as the number m decreases.Therefore, if the accuracy in detection of the size and the position ofan object is raised to enhance a performance, then it cannot be avoidedto reduce the area of one driving electrode DE. However, if the number mof driving electrodes DE is increased to reduce the electrode area, thenthe peak value of the detection signal of the touch sensor drops.

In the present example, the capacitance value Cp at a crossing locationwith a driving electrode DE varies in response to the area of onedriving electrode DE. In particular, as the area, particularly thewidth, of the driving electrode DE increases, also the capacitance valueCp increases. Further, as the area, particularly the width, of onesensor line SLi increases, also the capacitance value Cp increases.

Incidentally, if the sensor line SLi includes noise, then the signalcomponent, that is, an average peak value of the sensor voltages Vs andVf, relatively decreases with respect to the noise component in thedetection signal Vdet. Accordingly, the S/N ratio of the detectionsignal Vdet drops. The S/N ratio decreases as the number m of drivingelectrodes DE increases and the width of one driving electrode DEdecreases. Further, as the magnitudes of the signal component and thenoise component become close to each other, application of a noiseseparation technique becomes difficult. Particularly where the noisecomponent varies periodically and the period of the variation isproximate to the period of the detection signal, it becomes furtherdifficult to separate the noise.

Therefore, the sensitivity of the touch sensor, that is, the resolutionof the size of an object to be detected and the accuracy in positiondetection, and the S/N ratio of the detection signal Vdet have atradeoff relationship to each other, and even if a noise separationtechnique such as a noise filter is applied, it is difficult to improveboth of them.

Therefore, in the embodiment of the present invention, as a morepreferable mode, a period or cycle which does not involve any signalcomponent is provided intentionally to facilitate detection of a noisecomponent. If the noise component detected within the period or cycle issubtracted from a sensor line output within a period which involves bothof a signal component and a noise component, then noise removal can becarried out readily. It is to be noted that description of a particularcircuit of the noise removing section is omitted herein.

2. Second Embodiment

The second embodiment relates to a display apparatus according to thepresent invention. The display apparatus has a touch sensor functionsame as that of the display apparatus of the first embodiment.

The display apparatus according to the present embodiment is a liquidcrystal display apparatus which uses Vcom driving.

The present invention does not essentially require the Vcom driving.However, the liquid crystal display apparatus described below isgenerally configured such that it uses the Vcom driving and uses acommon electrode or opposing electrode for display driving also forsensor driving to carry out display scanning or writing scanning andsensor driving scanning simultaneously.

At this time, the display driving and the detection driving arepreferably synchronized with each other. In other words, in the presentembodiment, a driving electrode for the display driving, that is, anopposing electrode, is used also as a driving electrode for the sensordriving in order to achieve synchronous driving.

It is to be noted that, for such synchronization, a configuration whichgenerates a synchronizing signal such as a clock signal under thecontrol of a CPU or the like not shown in the display apparatus may beadopted, or a synchronizing signal may be supplied from the outside.Where the display apparatus is a display part such as a liquid crystaldisplay panel, also external synchronization is supposed. On the otherhand, where the display apparatus is a system including a display partsuch as a television apparatus, a monitor apparatus or some otherelectronic apparatus, a synchronizing signal is generated in the system.

This liquid crystal display apparatus is advantageous in that reductionin thickness of the entire apparatus can be achieved. However, if thedisplay driving frequency and the sensor driving frequency, that is, thedetection driving frequency, are set equal to each other, then thisgives rise to a disadvantage in a different aspect that theresponsibility upon sensor detection is degraded. Therefore, theadvantage described hereinabove in connection with the first embodiment,that is, the advantage that the responsibility in sensor detection isimproved without raising the detection driving frequency or even wherethe detection driving frequency is lowered conversely.

It is to be noted that the term “opposing electrode” in the presentspecification signifies an electrode which plays both of a role of acommon electrode or display driving electrode for display driving andanother role of a detection driving electrode for touch detectionsimilarly as in the first embodiment. In the following, in order tomaintain the consistency with the first embodiment, the term “drivingelectrode DE” which is used in the description of the first embodimentis used continuously.

Although the sensor detection accuracy increases in proportion to thenumber of sensor lines, which are also referred to as “detectionelectrodes” in the description of the present embodiment, if the sensorlines are disposed in a matrix in the x direction and the y direction,then the number of sensor lines becomes very great. In order to reducethe number of sensor lines, it is preferable to use a driving method ofAC driving one of a plurality of driving electrodes and shifting anoperation object of the AC driving within an array of a plurality ofdriving electrodes juxtaposed in a fixed pitch. A basic concept of thisdriving method is adopted also in the first embodiment, and therefore,only sensor lines elongated in the y direction can be used to providesensor outputs.

While a technique of AC driving an object of the AC driving in ascanning direction, that is, in the y direction, in accordance with apredetermined algorithm, is used, a potential variation of the sensorlines is observed following up the driving operation. Consequently,touch or proximity of a detection object can be detected from theaddress of a sensor line or detection electrode which exhibits apotential variation such as, for example, a drop of the pulse peak valueshown in FIG. 3A and the timing of the potential variation. This itselfis similar to that in the first embodiment.

Further, that a jump shift is included in the predetermined algorithmand an advantage by this, that is, improvement in latency, are similarto those in the first embodiment. Also it is similar as in the firstembodiment that the jump shift includes a shift between regions and acontinual jump shift.

In the following, a configuration and operation of the display apparatusare described first and then a preferable form of shift operation isdescribed.

General Configuration of the Display Apparatus

FIGS. 6A to 6C show arrangement of electrodes of the display apparatusaccording to the present embodiment and circuits for driving anddetecting the display apparatus. Meanwhile, FIG. 6D shows a schematicsectional structure of the display apparatus. FIG. 7 shows an equivalentcircuit diagram of a pixel of the display apparatus.

The display apparatus shown in FIGS. 6A to 6D is a liquid crystaldisplay apparatus which includes a liquid crystal layer as a “displayfunction layer.”

The liquid crystal display apparatus includes an electrode, that is, adriving electrode, provided on one of two substrates opposing to eachother with a liquid crystal layer interposed therebetween. The drivingelectrode is common to a plurality of pixels, and a common drivingsignal Vcom which provides a reference voltage to a signal voltage forgradation display for each pixel is applied to the driving electrode.

In FIG. 6D, in order to facilitate recognition of a sectional structure,the driving electrode, pixel electrodes and detection electrodes whichare principal components of the display apparatus are indicated byslanting lines while the other components such as the substrates,insulating films, functional films and so forth are shown withoutslanting lines. Such omission of slanting lines applies similarly to anyother view showing a sectional structure.

The liquid crystal display apparatus 1 includes a plurality of pixelsPIX shown in FIG. 7 which are arranged in a matrix. Referring to FIG. 7,each pixel PIX includes a thin film transistor (hereinafter referred toas TFT 23) as a select element of a pixel, an equivalent capacitance C6of a liquid crystal layer 6, and a holding capacitor Cx as an additionalcapacitor. The equivalent capacitance C6 representing the liquid crystallayer 6 is connected at one electrode thereof to a pixel electrode 22which is one of a plurality of pixel electrodes 22 separated forindividual pixels and arranged in a matrix. The other electrode of theequivalent capacitance C6 is a driving electrode 43 which is common tothe plural electrodes.

The pixel electrode 22 is connected to one of the source and the drainof the TFT 23, and an image signal line SIG is connected to the other ofthe source and the drain of the TFT 23. The image signal line SIG isconnected to a vertical driving circuit not shown such that an imagesignal having a signal voltage is supplied from the vertical drivingcircuit to the image signal line SIG.

To the driving electrode 43, the common driving signal Vcom is applied.The common driving signal Vcom is a signal having a center potential andpositive and negative potentials with reference to the center potentialand appearing alternately for every one horizontal period (1H).

The gate of the TFT 23 is electrically common among all pixels PIXjuxtaposed in a row direction, that is, in the horizontal transversedirection of the display screen, thereby to form a scanning line SCN.The scanning line SCN is supplied with a gate pulse outputted from thevertical driving circuit not shown for opening and closing the gate ofthe TFTs 23. Therefore, the scanning line SCN is referred to also asgate line.

Referring to FIG. 7, the holding capacitor Cx is connected in parallelto the equivalent capacitance C6. The holding capacitor Cx is providedin order to prevent the writing potential from being lowered by leakagecurrent of the TFT 23 because the storage capacity is insufficient withthe equivalent capacitance C6. The addition of the holding capacitor Cxis effective also to prevention of flickering and improvement inuniformity of the screen luminance.

As viewed in the sectional structure shown in FIG. 6D, the liquidcrystal display apparatus 1 includes a substrate 2 (hereinafter referredto as driving substrate 2) on which a TFT 23 is formed at a place whichdoes not appear on the cross section and to which a driving signal orsignal voltage for the pixels is supplied. The liquid crystal displayapparatus 1 includes an opposing substrate 4 disposed in an opposingrelationship to the driving substrate 2, and a liquid crystal layer 6disposed between the driving substrate 2 and the opposing substrate 4.

The driving substrate 2 includes a TFT substrate 21 which serves as acircuit board on which the TFT 23 of FIG. 7 is formed and which has abody portion made of glass or the like, and a plurality of pixelelectrodes 22 arranged in a matrix on the TFT substrate 21.

Display drivers not shown including a vertical driving circuit, ahorizontal driving circuit and so forth for driving the pixel electrodes22 are formed on the TFT substrate 21. Further, such TFTs 23 as shown inFIG. 7 and wiring lines such as image signal lines SIG and scanninglines SCN are formed on the TFT substrate 21. The touch detectionsection 8 described hereinabove with reference to FIGS. 4A and 4B in thedescription of the first embodiment is formed on the TFT substrate 21.

The opposing substrate 4 includes a glass substrate 41, a color filter42 formed on one face of the glass substrate 41, and a driving electrode43 formed on the color filter 42 adjacent the liquid crystal layer 6.The color filter 42 is formed from color filters of, for example, threecolors of red (R), green (G) and blue (B) arrayed periodically, and oneof the three colors of R, G and B is associated with each pixel PIX,that is, with each pixel electrode 22. It is to be noted that a pixelwith which one color is associated is referred to as sub pixel, and subpixels of the three colors of R, G and B are sometimes referred to aspixel. However, also a sub pixel is referred to as pixel PIX here.

The driving electrode 43 serves also as the driving electrode DE (referto the first embodiment) of a touch detector sensor which forms part ofa touch sensor for carrying out touch detection operation. The drivingelectrode 43 corresponds to the driving electrode E1 in FIGS. 1A to 2B.

The driving electrode 43 is connected to the TFT substrate 21 by acontact conducting column 7. The common driving signal Vcom having an ACpulse waveform is applied from the TFT substrate 21 to the drivingelectrode 43 through the contact conducting column 7. The common drivingsignal Vcom corresponds to the AC pulse signal Sg supplied from the ACsignal source AS of FIGS. 1A to 2B.

The sensor lines SL are formed on the face of the glass substrate 41adjacent the display face, and a protective layer 45 is formed on thesensor lines SL. The sensor lines SL form part of the touch sensor andcorrespond to the detection electrodes E2 in FIGS. 1A to 2B. The touchdetection section 8 shown in FIG. 4A for carrying out touch detectionoperation may be formed on the glass substrate 41.

The liquid crystal layer 6 serves as a “display function layer” andmodulates light which passes therethrough in the thicknesswisedirection, that is, in an opposing direction to the electrode, inresponse to the state of an electric field applied thereto. The liquidcrystal layer 6 is formed using a liquid crystal material of any ofvarious modes such as, for example, the TN (twisted nematic) mode, VA(vertical alignment) mode and ECB (electric field controllingbirefringence) mode.

It is to be noted that an orientation film is disposed between theliquid crystal layer 6 and the driving substrate 2 and between theliquid crystal layer 6 and the opposing substrate 4. Further, apolarizing plate is disposed on a face of the driving substrate 2 remotefrom the display face, that is, on the rear face side and also on a faceof the opposing substrate 4 adjacent the display face. Such opticalfunction layers as just mentioned are omitted in FIGS. 6A to 6D.

Example of a Basic Configuration of the Touch Detection Section

FIG. 8 shows a circuit of the voltage detector DET which is a basiccomponent of the touch detection section 8 in the present embodiment.

Referring to FIG. 8, the voltage detector DET includes an operationalamplifier 81, a rectification circuit 82 and an outputting circuit 83.

The components of the voltage detector DET are described successivelywith reference to FIG. 8.

In the voltage detector DET, the operational amplifier 81 includes anoperational amplifier 84, resistors R, R1 and R2, and a capacitor C3 andis configured so as to function not only as a signal amplificationcircuit but also as a filter circuit. In particular, the operationalamplifier 81 amplifies a detection signal Vdet outputted from adetection electrode 44, removes a predetermined frequency component fromthe detection signal Vdet and outputs a resulting signal to therectification circuit 82.

In particular, in the operational amplifier 81, the detection electrode44 is electrically connected to a non-inverting input “+” of theoperational amplifier 84 such that the detection signal Vdet outputtedfrom the detection electrode 44 is inputted to the non-inverting inputterminal of the operational amplifier 84. Here, the detection electrode44 is connected to a ground potential through the resistor R in order toelectrically fix the DC level of the potential. Meanwhile, the resistorR2 and the capacitor C3 are connected in parallel between the invertinginput “−” and the output of the operational amplifier 84, and theresistor R1 is connected between the inverting input “−” and the groundpotential.

In the voltage detector DET, the rectification circuit 82 includes adiode D1, a charging capacitor C4, and a discharging resistor R0. Therectification circuit 82 is configured such that a signal outputted fromthe operational amplifier 81 is half-wave rectified by the diode D1first and is then smoothed by a smoothing circuit formed from thecharging capacitor C4 and the discharging resistor R0. Then, thesmoothed signal is outputted to the outputting circuit 83.

In particular, in the rectification circuit 82, the diode D1 iselectrically connected at the anode thereof to the output terminal ofthe operational amplifier 81. The charging capacitor C4 and thedischarging resistor R0 are electrically connected individually betweenthe cathode of the diode D1 and the ground potential.

In the voltage detector DET, the outputting circuit 83 includes acomparator 85 and is configured such that it functions as an ADconverter for converting an analog signal outputted from therectification circuit 82 into a digital signal.

In particular, the comparator 85 is electrically connected at anon-inverting input terminal (+) thereof to the rectification circuit82. Further, a threshold voltage Vth is inputted to the negative inputterminal (−) of the comparator 85. The comparator 85 carries out acomparison process of the analog signal outputted from the rectificationcircuit 82 with the threshold voltage Vth and outputs a digital signalbased on a result of the comparison process.

Such voltage detectors DET are disposed in a juxtaposed relationship,for example, on one end side of the opposing substrate 4 in alongitudinal direction of the detection electrode 44 around the displayregion thereby to form the touch detection section 8. It is to be notedthat the touch detection section 8 whose basic configuration is thevoltage detector DET may be disposed on the other end side or on theopposite end sides of the detection electrode 44. Where the touchdetection section 8 is disposed on the opposite end sides, for example,those voltage detectors DET which correspond to odd-numbered ones of thedetection electrodes 44 may be disposed on one end side in thelengthwise direction of the detection electrodes 44 while those voltagedetectors DET which correspond to even-numbered ones of the detectionelectrodes 44 are disposed on the other end side.

Configuration of the Driving Electrodes and Driving Scanning

The driving electrode 43 is divided in the direction of a row or acolumn of the pixel array as seen in FIG. 6A, in the present example, inthe direction of a column, that is, in a vertical direction in FIG. 6A.The direction of the division corresponds to a scanning direction of apixel line in display driving, in particular, in a direction in whichthe vertical driving circuit not shown successively activates thescanning lines SCN.

The driving electrode 43 is divided into totaling k×m electrodes.Therefore, the driving electrodes 43_1, 43_2, . . . , 43_k, . . . ,43_km are disposed in a plane such that they have a belt-like patternelongated in the row direction and spread in parallel to each other andin a mutually spaced relationship in the plane.

The divisional arrangement pitch of the k×m divisional drivingelectrodes 43_1 to 43_km is set equal to the (sub) pixel pitch or to anatural number of times the arrangement pitch of the pixel electrodes.Here, it is assumed that the divisional arrangement pitch of the drivingelectrodes is equal to the arrangement pitch of the pixel electrodes.

It is to be noted that the reference character “DE” (DE1, DE2, DE3, . .. , DEm) in FIGS. 4A and 4B represents a set of k (>2) drivingelectrodes, and AC driving is carried out in a unit of this number ofdriving electrodes. This unit corresponds to the driving electrode DE inthe first embodiment. The reason why the unit of the AC driving is setgreater than one pixel line is that it is intended to increase thecapacitance of the touch sensor to raise the detection sensitivity. Onthe other hand, it is possible to shift the driving electrode DE by anamount equal to a natural number of times the arrangement pitch unit tomake the shift invisible.

On the other hand, in the Vcom driving which is carried out in a unit ofa driving electrode DE in this manner, the shift operation is carriedout by the scanning driving section 9 provided in the vertical drivingcircuit not shown, that is, the writing driving scanning section, andserving as a “detection scanning control section.” A predeterminedalgorithm executed by the scanning driving section 9 is the same as thepredetermined algorithm whose outline is described hereinabove inconnection with the first embodiment.

Meanwhile, the n sensor lines SL1 to SLn are formed from wiring lines ofparallel stripes elongated in the y direction similarly as in the firstembodiment. The n sensor line outputs from the n sensor lines SL1 to SLnare inputted to the touch detection section 8.

It is to be noted that FIGS. 6A and 6B show the electrode patterns ofthe driving electrodes 43_1 to 43_km and the sensor lines SLiseparately, respectively. However, actually the driving electrodes 43_1to 43_km and the sensor lines SLi are disposed in an overlappingrelationship as seen in FIG. 6C.

By the configuration just described, the touch detection section 8 candetect a position in the row direction depending upon with whichdetection circuit DET a voltage variation occurs and can acquireposition information in a column direction depending upon the timingupon such detection. In other words, it is assumed that the Vcom drivingof the scanning driving section 9 and operation of the touch detectionsection 8 are carried out in synchronism with each other, for example,by a clock signal of a predetermined period. Since it can be found bysuch synchronous operation as described above which one of the drivingelectrodes the scanning driving section 9 is driving at the timing atwhich the touch detection section 8 acquires a voltage variation, thecenter of the touching position of a finger can be detected. Suchdetection operation is controlled by a computer-based supervisorycontrol circuit which supervises the entire liquid crystal displayapparatus 1, for example, a CPU, a microcomputer or a control circuitfor touch detection.

While the scanning driving section 9 as the “detection scanning controlsection” is formed on the driving substrate 2 side of FIG. 6D, the touchdetection section 8 may be formed on the driving substrate 2 or may beformed on the opposing substrate 4 side or else may be disposedexternally of the liquid crystal display apparatus 1.

Since many TFTs are integrated, in order to reduce the number offabrication steps, preferably the touch detection section 8 can beformed together with the driving substrate 2. However, the sensor linesSL are sometimes provided on the opposing substrate 4 side, and sincethe sensor lines SL are formed from a transparent electrode material,they sometimes have high wiring line resistance. In such a case, inorder to avoid the drawback that the wiring line resistance is high,preferably the touch detection section 8 is formed on the opposingsubstrate 4 side. However, if a TFT formation process is used for theopposing substrate 4 only for the sake of the touch detection section 8,then this gives rise to a disadvantage that an increased cost isrequired. The formation position of the touch detection section 8 may bedetermined taking such advantages and disadvantages as described aboveinto consideration.

Lateral Field Mode Liquid Crystal Display Apparatus

FIG. 9 shows a schematic sectional structure of a display apparatus of amore preferable structure according to the second embodiment.

The liquid crystal display apparatus shown in FIG. 9 is different fromthe liquid crystal display apparatus shown in FIG. 6D in that thedriving electrode 43 is disposed on the driving substrate 2 side. Thedriving electrode 43 in the present embodiment is disposed in anopposing relationship to the pixel electrodes 22 on the opposite side tothe liquid crystal layer 6 with respect to the pixel electrodes 22.Here, though not particularly shown, the distance between the pixelelectrodes 22 is comparatively great such that the driving electrode 43generates an electric field so as to act upon the liquid crystal layer 6from between the pixel electrodes 22. In other words, liquid crystaldisplay of the lateral field mode wherein the direction in which theelectric field acts upon the liquid crystal layer 6 is the lateraldirection is obtained. The configuration of the other part of the liquidcrystal display apparatus is similar, in regard only to the arrangementon a cross section, to that shown in FIG. 6D.

Since the capacitance element C1 is formed between a sensor line SL andthe driving electrode 43, the capacitance value is lower than that inthe case of FIG. 6D. However, such a countermeasure as to compensate forincrease of the distance between the electrodes by means of increase ofthe width of electrodes is possible, and the sensitivity may possibly beraised from a relationship with the capacitance element C2.

The liquid crystal layer 6 modulates light which passes therethrough inresponse to the state of an electric field, and liquid crystal of alateral field mode such as, for example, the FFS (fringe fieldswitching) mode or the IPS (in-plane switching mode) is used for theliquid crystal layer 6.

In the following, several forms of particular shift operation aredescribed as examples where the regular shift operation describedhereinabove in connection with the first embodiment is applied to aliquid crystal apparatus according to the second embodiment.

First Example of Shift Operation

FIG. 10A schematically illustrates transition of a driving electrode ofa voltage application object in a first example of shift operation. InFIG. 10A, three sensor lines SL are indicated by a vertical blank linefor the convenience of illustration. Further, a portion indicated byhorizontal stripe lines represents a driving electrode DE, and a singleblack horizontal line represents a display pixel line PL. A broken linearrow mark indicated along an axis of ordinate in FIG. 10A indicates abasic scanning direction. It is to be noted that, in FIG. 10A, a planview for nine cycles when the time elapses from the left toward theright in the figure is shown. It is to be noted that one cyclecorresponds to a 1H horizontal period in display control.

In FIG. 10B, pulses of gate signals Gate(N) to Gate(N+8) to be appliedto a scanning line SCN in the first example of shift operation andpositions of the driving electrode DE upon application of the pulses areillustrated as a schematic timing chart. In FIG. 10B, a portion definedby a thick broken line indicates a range of a driving electrode DE of avoltage application object. The axis of ordinate in FIG. 10B indicatesthe address of pixel lines and the axis of abscissa indicates time. Asthe addresses of pixel lines, only necessary ones of referencecharacters “Line(N) to Line(N+8)” and reference characters “Line(M) toLine(M+8)” are shown.

A region which includes the reference characters “Line(N) to Line(N+8)”is hereinafter referred to as region A and another region which includesthe reference characters “Line(M) to Line(M+8)” is hereinafter referredto as region B.

The first example of shift operation is characterized in that, bycarrying out jump shift between two regions such as the region A and theregion B, detection driving is carried out alternately between the tworegions. Thereupon, odd-numbered driving electrodes DE_A1, DE_A2, . . ., DE_A5 selected in the region A exhibit timings overlapping with thoseof odd-numbered pulses of the gate signals Gate(N) to Gate(N+8) ofdisplay driving. Therefore, it is necessary for the display drivingvoltage Vcom and the detection driving voltage COM to be a commonvoltage. In other words, the magnitude of the detection driving voltageCOM is set equal to that of the common driving signal Vcom.

It is to be noted that, as regards expression of the detection drivingvoltage COM, for example, the first detection driving voltage COM isrepresented by a reference character “COM(N) to COM(N−α).” For example,in the present example, α is α=4, and five driving electrodes DE aredriven simultaneously. Where α is α=0, the driving electrodes DE aredriven one by one. However, since, in FIGS. 5A to 5C, “m” becomes great,the detection sensitivity drops. Therefore, normally it is desirable toset α to a comparatively high value.

Further, in the first example of shift operation, in both of the regionA and the region B, the shift width of the driving electrode DEcorresponds to two pixel lines and has a comparatively small shiftamount. In particular, for example, in regard to the region A, it can berecognized from FIG. 10B that the first driving electrode DE_A1 and thenext driving electrode DE_A2 exhibit a shift amount corresponding to twolines. This is because, if the shift amount is increased in the sameregion, then changeover between driving electrodes stands out.

It is to be noted that, since such suppression of the shift amount isfor eliminating such a fault that changeover stands out by applicationto a display apparatus, a detection apparatus by itself exhibits lownecessity as in the first embodiment. However, in regard to the sameregion, control is facilitated where the shift amount is reduced.Further, since the driving electrode 43 (basic configuration of thedriving electrode DE) to be added newly or to be excepted newly islimited to two preceding and succeeding lines, a small shift amount isdesirable in the same region in order to suppress power consumption andachieve stabilized operation.

On the other hand, since the driving electrodes DE repeat movement of adriving object between regions for every one cycle (1H), objectdetection at a comparatively early stage is possible in comparison withsequential scanning. Roughly speaking, in the case of division into tworegions, the probability that an object such as a finger or a stylus penis detected in a period of time of one half becomes highest.

Since α is α=4 and five driving electrodes 43 are included in onedriving electrode DE, the value of m in the expression given in FIG. 5Cis reduced to ⅕ the actual dividing number and the effective value ofthe sensor voltage Vs increases as much. On the other hand, the unit tobe newly included into a selection group (driving electrode DE) and tobe removed from the selection group instead corresponds to two pixellines as seen in FIGS. 10A and 10B. This shift operation for every twopixel lines is finer in pitch or shift amount of the shift operation incomparison with shift operation which repeats changeover of five pixellines with different five pixel lines adjacent the five pixel lines.Since the shift amount is smaller, in the shift operation for every twopixel lines, an image variation arising from the shift of AC driving isless likely to be visually observed by the eye of human beings. In thisregard, shift operation for every one pixel line is more desirable.However, where the shift amount is excessively small, then much time isrequired for detection scanning over the entire one screen. Further,since the size of a detection object such as a finger or a stylus pen issufficiently greater than the pitch of the pixel lines, in most cases,the high detection accuracy by shift amount for every one pixel line ismore than sufficient.

From the foregoing, the shift amount of the driving electrode DE shouldbe determined totally taking to make shift of the driving electrode DEinvisible, the detection time period for one pixel and the detectionaccuracy into consideration.

In the following, several examples of shift operation are described withreference to FIGS. 11A and 11B to 17A and 17B similar to FIGS. 9A and9B. Since the manner of representation of the figures is describedhereinabove in connection with FIGS. 10A and 10B, only differences inshift operation from those in FIGS. 10A and 10B are described below.

Second Example of Shift Operation

In a second example of shift operation illustrated in FIGS. 11A and 11B,although the dividing number of the region is the same as that in thecase of FIG. 9, sequential shift operation for the individual pixellines is carried out twice in the region A, jump shift operation to theregion B is carried out. Similarly, after sequential operation for theindividual pixel lines is carried out twice in the region B, jump shiftoperation to the region A is carried out.

By repetitions of the operation, sequential shift operation is carriedout with the three driving electrodes DE in the two regions includingthe region A and the region B. Therefore, detection operation carriedout alternately in the region A and the region B for every 3H.

Third Example of Shift Operation

In a third example of shift operation illustrated in FIGS. 12A and 12B,the dividing number of the region is increased by one and therefore tothree. A region including addresses “Line(L) to Line(L+6)” of pixellines in FIG. 12B is hereinafter referred to as region C.

Movement between regions is carried in order of the region B, region Aand region C as seen in FIGS. 12A and 12B, and this is repeated. While,in the present example, display of a display pixel line PL and thedriving range of the driving electrode DE overlap with each other in theregion A, such overlap is likely to appear also in the region B and theregion C.

In the present example, jump shift operation is repeated successively inthe three regions of the region B, region A and region C, and detectionoperation between different regions of one display screen is carried outfor every 1H.

Fourth Example of Shift Operation

In a fourth example of shift operation illustrated in FIGS. 13A and 13B,the dividing number is three similarly as in the third example of shiftoperation. However, in the present example, after sequential shiftoperation for the individual pixel lines is carried out twice in eachregion, jump shift operation to a next region is carried out similarlyas in the second example of shift operation.

Movement between regions is carried out in order of the region B, regionA and region C similarly to the movement of a driving object describedhereinabove with reference to FIGS. 12A and 12B, and this is repeated.While, in the present example, display of a display pixel line PL andthe driving range of the driving electrode DE overlap with each other inthe region A, such overlap is likely to occur also in the region B andthe region C.

In the present example, jump shift operation is repeated successively inthe three regions of the region B, region A and region C, and besidessequential shift operation is carried out in the three drivingelectrodes DE in each region. Therefore, detection operation is carriedout successively in the three regions of the region B, region A andregion C for every 3H.

Fifth Example of Shift Operation

In a fifth example of shift operation illustrated in FIGS. 14A and 14B,the dividing number of the region is set to three similarly as in thethird example of shift operation. Further, jump shift operation iscarried out basically every time similarly as in the third example ofshift operation. However, in the fifth example of shift operation,detection operation in the region C is not carried out, and therefore,detection driving for a period of 2H and a halting period for 1H arerepeated. For example, if the region C is a display screen region whichdoes not include an operation section in a display application or thelike, then touch detection in the region C makes no sense. Thus,detection operation in such region C is halted.

Within the halting period of touch detection, only jump shift operationbetween regions is carried out, but actual application of the detectiondriving voltage COM is not carried out. Therefore, during a periodcorresponding to the 1H period of the sensor line output, only noisecomponents are superposed. Accordingly, the sensor line output withinthe halting period can be used to carry out the noise removing processdescribed in connection with the first embodiment.

Sixth Example of Shift Operation

In the fifth example of shift operation described above, a periodcorresponding to the region C is used as the halting period.

In contrast, in a sixth example of shift operation illustrated in FIGS.15A and 15B, a halting period within which detection operation is notcarried out in any region is provided periodically, for example, forevery 3H. Such an example of shift operation as just described is usedsuitably, for example, in the following case. In particular, there isthe possibility that an operation may be carried out for any region ofthe effective display screen, and if touch detection is not carried outonly for a particular region, then some inconvenience may occur. In suchan instance, a halting period should be provided periodically as in thecase of the sixth example.

As operation within the halting period of touch detection, only jumpshift operation between regions is carried out but actual application ofthe detection driving voltage COM is not carried out similarly as in thefifth example of shift operation. Therefore, the sensor line outputexhibits a period within which only noise components are superposed at arate of one 1H period to a 3H period. Accordingly, the sensor lineoutput within the halting period can be used to carry out the noiseremoving process described hereinabove in connection with the firstembodiment.

The foregoing six examples of shift operation which involve movement ofa driving object between regions are mere examples, and the regiondividing number and the manner of provision of a halting period can bedetermined arbitrarily. For example, as regards the dividing number, thedividing number of regions may be determined in response to the size ofthe detection face and so forth. Further, where the region dividingnumber is great, shift operation for one screen may be carried outincluding jumping over of regions. In particular, while, in the first tosixth examples of shift operation, the movement of a driving objectbetween regions by jump shift is always movement to a next adjacentregion, jump shift to a region spaced by more than one region distanceother than a next adjacent region can be carried out. After such regionjump shift is carried out for one screen, a driving object is moved byregion jump shift to the remaining regions. Such a sequence of movementis repeated until all regions of the screen are scanned. Such jumpingover shift operation wherein the driving object moves jumping over aregion or regions is preferable in a sense that an object can bedetected at a comparatively early stage.

Now, two examples of operation wherein jump shift is carried outnormally during scanning of one screen.

Seventh Example of Shift Operation

FIGS. 16A and 16B schematically illustrate a seventh example of shiftoperation.

FIG. 16A illustrates pulses of a gate signal (Gate(M) to Gate(N) (N>M))to be applied to the scanning line SCN in the seventh example of shiftoperation and positions of the driving electrodes DE upon application ofthe pulses. The broken line representation of a range of a drivingelectrode DE in FIG. 10B and the representation of the axis of ordinateand the axis of abscissa of FIGS. 10A and 10B are the same as those ofthe other examples of operation described hereinabove. While the addressof a pixel line is indicated by reference character “Line(M) toLine(N),” and the address of pixel lines in the proximity of a middleone of the N vertical pixel lines is indicated by reference characters“Line(N/2−2) to Line(N/2+3).” It is to be noted that the referencecharacter “M” represents the address of a pixel line positioned on oneend side of the screen which is greater than one, and several ten toseveral hundred pixel line addresses exist between the addresses “M+3”and “N/2−2.” Similarly, several ten to several hundred pixel lineaddresses exist between the addresses “N/2+3” and “N−2.”

In the seventh example of shift operation, display driving is carriedout for one by one pixel line for every one horizontal period (1H).

Shift operation between the driving electrodes DE is repeated takingthis 1H as one cycle. At this time, in the present example of operation,upon transition from one cycle (1H) to a next one cycle (1H), shift bytwo pixel lines is carried out, and within the period, also the writingline or display line advances by one line distance. Therefore, therelative line conversion speed difference corresponds to two lines, andthis is hereinafter referred to as two-line jump. The jump line numberK=2 at this time represents the relative shift ratio of the shift as itis, and in the present example, the shift is double-speed shift.

In the present example of operation, since double speed shift is carriedout, detection scanning for two screens is carried out within a periodfor writing scanning or display scanning for one screen. In short, atechnique of “carrying out detection driving scanning for two (=N+1)screens within a period for display driving scanning for one (=N)screen” corresponds to the seventh example of shift operation.

Eighth Example of Shift Operation

FIGS. 17A and 17B schematically illustrate an eighth example of shiftoperation. The manner of representation of FIGS. 17A and 17B is similarto that of FIGS. 16A and 16B.

In the present example of shift operation, upon transition from onecycle (1H) to a next one cycle (1H), shift by three pixel lines iscarried out. However, within this period, also the writing line, thatis, the display line, advances by one line. Therefore, the relative lineconversion speed difference corresponds to three lines, and this ishereinafter referred to as three-line jump. The jump line number K atthis time is K=3, and this represents as it is the relative speed ratioof shift. In the present example, the manner of shift is triple-speedshift.

In the present example of operation, since the manner of shift istriple-speed shift, detection scanning for three screens is carried outwithin a period of writing scanning or display scanning for one screen.In other words, a technique of “carrying out detection driving scanningfor three (>N+1) screens within a period of display driving scanning forone (=N) screen” is the eighth example of shift operation.

The two examples of operation of continual jump shift described aboverelate to cases wherein N=1 and M is 2 and 3. However, N and M may havearbitrary values. It is to be noted that the value of N is not limitedto a natural number equal to or higher than 2 but may be a fractionhigher than 1 such as 3/2, 4/2, 4/3, 5/2, 5/3, 5/4, . . . . Further,where an operation stopping period for a fixed number of lines isprovided between frames or in a like case, N may not be represented as afraction.

Also it is possible to use detection scanning wherein jump is carriedout completely such that a display pixel line for which display scanningis being carried out and a detection line for which detection scanningis being carried out do not overlap with each other. In this instance,although several lines may not undergo detection scanning, since suchseveral non-detection lines do not matter with respect to a fingertip ora stylus pen of a detection object, object touch or object detection canbe carried out normally.

From the foregoing, the concept of the shift technique with regard towhich the seventh and eighth examples of shift operation are given asparticular examples can be regarded as “to carry out detection drivingscanning for N+1 screens or more within a period of display drivingscanning for N screens.”

The technique wherein continual jump scanning is carried out within ascanning period for one screen as in the seventh and eighth examples ofshift operation has an advantage that, since it is sequential scanningin one direction, the configuration of the driving system circuitincluding the scanning driving section 9 can be simplified. Further,while the touch detection section 8 carries out touch detection insynchronism with the scanning driving section 9, a timing at which asensor voltage variation occurs within a scanning period of one screenis likely to be decided as a position in a screen at which touch orproximity occurs.

Therefore, also the configuration of the touch detection section 8 canbe simplified. Also the processing burden on the control circuit such asa CPU for controlling various driving circuits including the touchdetection section 8 and the scanning driving section 9 is reduced.

Further, where the application voltage upon display scanning and theapplication voltage upon detection scanning are set equal to each other,there is no interference between a pixel line for which display drivingis being carried out and another pixel line for which detection scanningis being carried out, and even if such interference should occur, it isvery little.

Where detection scanning is carried out completely jumping over a pixelline under display scanning described hereinabove, since the detectiondriving voltage COM can be controlled independently of the commondriving signal Vcom, even if the two voltages are set to differentapplication voltages, they do not interfere with each other. However, inthe case of complete jumping over, display driving and detection drivingmust be essentially required.

From the foregoing, such a disadvantage that one of display driving anddetection driving interferes with the other of them to deteriorate thedisplay quality or to give rise to a detection error can be prevented.

It is to be noted that such control as to prevent a pixel line group fordetection driving, that is, the range of the driving electrodes DE, andthe display pixel line PL from overlapping with each other anytime canbe carried out also by detection driving scanning which involves shiftbetween regions as in the first to sixth examples of shift operation.

In the first to eighth examples of shift operation, except a periodwithin which driving halting is carried out, when the writing line ordisplay line advances by a one-line distance, a shift of the drivingelectrode DE is carried out without fail. The shift of the drivingelectrode DE is not limited to this.

For example, a period within which the display line advances a distanceof a predetermined number of lines greater than one is set as a standbyperiod within which a shift of the driving electrode DE is not carriedout. Then, a shift of the driving electrode DE is carried out after thestandby period in which the display line advances by the distance of thepredetermined number of lines comes to end.

It is possible to carry out the detection driving scanning where therepetitions of the standby and the shift (hereinafter referred to asshift operation with standby) are determined as one cycle.

It is to be noted that, where the halting period described hereinaboveis provided, a driving halting period for one cycle or more within whichapplication of the detection driving voltage is not carried out althoughthe shift is carried out or within which none of a shift and applicationof the voltage is carried out is provided at a ratio of once to severalcycles.

In contrast, the standby period is different from the halting period inthat it is a period which is set short within one cycle and within whichno shift is carried out from a relationship to the display linescanning.

It is to be noted that shift operation with standby may be used to carryout driving halting at a ratio of once to several cycles.

In particular, an example of shift operation with standby is described,for example, with reference to FIGS. 16A and 16B.

In the operation of FIGS. 16A and 16B, operation of advancing thedriving electrode DE of the width of five display lines shown in FIG.16B by a distance of two display lines when the display line advances bya one-line distance is carried out.

If shift operation with standby is applied to this operation, then, forexample, while the display line advances by two lines, the drivingelectrode DE is not shifted, but when the display line advances to thethird line, the driving electrode DE is shifted by a distance of fourpixel lines. In short, in the shift of the driving electrode DE of FIGS.16A and 16B, shift operation is carried out skipping once per twice, andinstead, after the standby, shift operation is carried out by a shiftamount equal to twice that in the FIGS. 16A and 16B, that is, by adistance of four display lines, after the standby.

Such shift operation with standby as described above can be carried outsimilarly also to the operation of FIGS. 17A and 17B. If this operationis generalized, then the shift operation with standby can be regarded asoperation of carrying out skipping shift operation at a ratio of T timesto S times where S is equal to or greater than 2, that is, S≥2, and T issmaller than S, that is, T<S.

However, the skipping operation described above is a mere example ofshift operation in which a standby period is provided. At least only itis necessary that the pixel line group for detection driving, that is,the range of the driving electrode DE, is two lines or more and besidesa standby period within which the driving electrode DE is not shiftedexists within a period within which the display line advances.

Now, two examples of a more particular configuration of the scanningdriving section 9 for the application of the detection driving voltageCOM which involves the shift operation described hereinabove aredescribed.

First Example of the Configuration of the Scanning Driving Section

FIG. 18 is a schematic block diagram of the liquid crystal displayapparatus 1 which detail displays a first example of a configuration ofthe scanning driving section.

In the liquid crystal display apparatus 1 shown in FIG. 18, a scanningdriving section 9A which corresponds to the scanning driving section 9of FIGS. 4A and 4B is disposed remotely from a gate driver with respectto the pixel array of the display section. The gate driver is a pulsegeneration circuit for a gate signal (Gate(j−1), Gate(j+1), . . . ) tobe applied to the scanning line SCN and serves as a vertical drivingcircuit.

While FIG. 18 shows four display pixel lines PL in the pixel array, theentire pixel array includes km display pixel lines PL.

Referring to FIG. 18, the scanning driving section 9A includes a shiftregister 91, a COM selection circuit (COM Select) 92, a COM buffer 93and a level shifter 94.

The shift register 91 receives a start pulse SP as an input thereto,transfers and retains the start pulse SP in synchronism with a clock.Then, the shift register 91 outputs km mutually synchronized outputpulses in parallel therefrom. If the start pulse SP is inputted by aplural number of times within a display period of one screen, thentransfer can be repeated every time.

The COM selection circuit 92 is a selection circuit for selectingwhether or not a detection driving voltage, in this instance, a COMpotential, is to be outputted to each of the km driving electrodes 43.The COM selection circuit 92 receives a control pulse CP as an inputthereto and passes a pulse from the shift register 91 only to a drivingelectrode 43 having a y address indicated by the control pulse CP.Further, the COM selection circuit 92 functions as a masking circuit forinhibiting passage of the pulse from the shift register 91 to the otherdriving electrodes 43. The information of whether such pulse passageshould be permitted or inhibited is provided to the COM selectioncircuit 92 through the control pulse CP generated in accordance with analgorithm for a predetermined shift operation.

Accordingly, where a driving electrode DE is formed from five certaindriving electrodes 43, the pulse passage is permitted only to five yaddresses corresponding to the driving electrode DE of the fivesuccessive driving electrodes 43 but is inhibited for the other yaddresses.

Further, where jump shift operation is carried out, pulse passage ispermitted for five y addresses spaced, for example, by a distance ofseveral ten to several hundred addresses and is inhibited for the five yaddresses for which the pulse passage has been permitted till then.

Further, where a halting period is provided, pulse passage isadditionally inhibited within the period or at y addresses correspondingto the particular region. Since the number of times of scanning for adisplay screen increases particularly in such continual jump shiftoperation like the seventh and eighth examples of shift operation,within the fly-back period or within a fixed period after the fly-backperiod, operation of the driving circuits may be substantially stoppedby such additional inhibition of pulse passage. The period within whichsubstantial driving control is stopped within a fixed period of timeafter the fly-back is determined, for example, taking the stability ofthe driving circuits into consideration.

Since the touch detection section 8 is operative within this haltingperiod, noise detection described hereinabove can be carried out makinguse of the halting period.

The level shifter 94 changes the potential of pulses sent thereto as aresult of passage permission by the COM selection circuit 92 so as tohave a voltage level sufficient for control.

The detection driving voltage COM generated in this manner is inputtedto the effective screen region through a final output buffer, that is,the COM buffer 93, or a final switch and is applied to a correspondingdriving electrode 43.

It is to be noted that a level control signal COMP of a COM pulse isinputted to the level shifter 94 such that the potential of the COMpulse can be varied, for example, between regions in response to thelevel control signal. Further, the phase of the COM pulse outputted fromthe COM buffer 93 may be varied, for example, between regions.

The intention that the amplitude or the phase of the COM pulse is variedbetween regions in this manner resides in that it is taken intoconsideration that it is difficult for the touch detection section 8(refer to FIGS. 6A to 6D) to carry out identification between regionsonly from the timing of sensor line outputting due to wiring line delay.In particular, if the amplitude or the phase of the COM pulse is variedbetween regions to vary the manner of driving between regions, then alsoit can sometimes be identified readily in which region the sensor lineoutput is generated. By varying the amplitude or the phase of the COMpulse in this manner, it is intended to raise the accuracy in touchdetection to assist this.

It is to be noted that, where the sequential shift operation is combinedwith the jump shift operation, a shift register for shift operation maybe provided in front of the level shifter 94.

The configuration shown in FIG. 18 may be replaced by a differentcircuit configuration wherein transfer logics independent of each otherare used to control a plurality of driving electrodes 43 for individualregions. However, this gives rise to a disadvantage that the controlcircuit scale becomes large and, in actual use, a peripheral section,that is, a picture frame, of the effective display region of the liquidcrystal display apparatus 1 becomes large and the power consumptionincreases.

Therefore, with the configuration shown in FIG. 18, there is anadvantage that, also where the transfer logic controls the drivingelectrodes 43 for the individual regions, the single scanning drivingsection 9A can be used for driving, and the increase of the pictureframe can be suppressed to the minimum and also the power consumptioncan be suppressed to the utmost.

It is to be noted that, since, in such continual jump shift operation asin the seventh and eighth examples of shift operation describedhereinabove, since the scanning is one-directional scanning suitable fora driving circuit configured on the basis of such a shift register asdescribed above, the configuration for output control of a pulse can beomitted or simplified significantly.

On the other hand, in operation which includes jump shift betweenregions as in the first and sixth examples of shift operation, sincefirst detection of a detection object is carried out early, theoperation is advantageous for improvement of the latency.

In order to improve the latency by continual jump shift operation, thevalue of K which is the line converted ratio of the relative speedshould be increased.

In this manner, improvement of the latency and suppression of increaseof the circuit burden have a tradeoff relationship, and which one of theshift operations described above should be selected is determineddepending upon which one of the improvement of the latency and thesuppression of increase of the circuit burden should be prior. Thelatency can be improved also by improvement of the driving frequency orthe processing speed of the image processing circuit. Further, althoughit depends upon application software or an application to be used, if itis taken into consideration that only it is necessary for a latencyhigher than a certain fixed level to be obtained, it is preferable touse the continual jump shift operation with which somewhat highpractical latency is obtained and which is advantageous in suppressionof the circuit burden and the cost.

Second Example of the Configuration of the Scanning Driving Section

FIG. 19 is a schematic block diagram of a liquid crystal displayapparatus 1 which shows details of a second example of a configurationof the scanning driving section.

In the configuration shown in FIG. 19, a function of a gate driverprovided separately in the configuration shown in FIG. 18 is provided inthe scanning driving section 9B.

For example, such a case that the arrangement region for a gate driverbecomes insufficient as a result of assurance of an arrangement regionfor a timing generation circuit (T/G) or a DC-DC converter as seen inFIG. 19 may occur.

In this instance, although it is possible to use transfer logicsindependent of each other, this increases the control circuit scale, andin practical use, such a disadvantage that the picture frame becomeslarge and the power consumption increases is invited. Thus, in FIG. 19,a function of a gate driver is provided in the scanning driving section9B.

One of differences of the scanning driving section 9B shown in FIG. 19from the scanning driving section 9A shown in FIG. 18 is that apermission control circuit (Enable Control) 95 is disposed on the outputside of the shift register 91. Further, in FIG. 19, a gate/COM selectioncircuit (Gate/COM Select) 96 is provided in place of the COM selectioncircuit 92 of FIG. 18. Furthermore, in FIG. 19, a gate/COM buffer 97 isprovided in place of the COM buffer 93 of FIG. 18.

The permission control circuit 95 permits pulse passage of a pulse fromthe shift register 91 similarly as in the permission control circuit 95of FIG. 18 and adds, to the pulse whose passage is permitted,information for identifying a y address corresponding to a display pixelline PL from which a gate pulse to be applied to a scanning line SCN isto be generated. For example, where a certain pulse from among aplurality of pulses whose passage is permitted corresponds to a displaypixel line, the permission control circuit 95 inverts and passes onlythe pulse therethrough.

The gate/COM selection circuit 96 permits passage only of a pulse of a yaddress corresponding to a driving electrode 43 to be controlled fordetection driving from a control pulse CP inputted thereto, and, if theinput pulse at this time is in an inverted state, the gate/COM selectioncircuit 96 permits also the inverted pulse therethrough.

The level shifter 94 changes the level only of a COM pulse for detectiondriving similarly as in the case of FIG. 18.

The gate/COM buffer 97 distributes only an inverted pulse to an outputpath for a gate signal (Gate) so as to be inverted and then applies thepulse to a scanning line SCN for the display pixel lines PL. Further,since the non-inverted pulse is the COM pulse whose level is adjusted,it is distributed and outputted to the output path of the drivingelectrode 43.

It is to be noted that the manner of adding information foridentification of a y address corresponding to a display pixel line PLis not limited to the pulse inversion but may be some other method.Further, the permission control circuit 95 and the gate/COM selectioncircuit 96 may be configured otherwise such that each of them receives apulse train as an input thereto from the shift register 91 and selectsand outputs a pulse corresponding to the y address to be outputted. Or,they may have a register configuration of two systems.

In the first and second embodiments described above, it is possible toimprove the detection speed without raising the detection drivingfrequency and detect a touch (or proximity) position without acomplicated sensor line structure or without increase of the number ofdetectors.

Since, at a certain moment, a potential variation for touch detectionwhich appears at a sensor line output corresponds to touch or proximityat one place, position detection is easy. Further, even if a pluralityof detection objects exist, it can be identified with which region eachdetection object touches or is proximate. At this time, since the TFT 23(refer to FIG. 7) is in an off state, even if the potential at thedriving electrodes other than that for the writing line fluctuates, thisdoes not have an influence on image display.

3. Modifications

At the top of the description of the embodiments of the presentinvention, it is described that the present invention can be applied notonly to a capacitance type apparatus but also to a resistance film typeapparatus and an optical type apparatus.

Where the present invention is applied to a resistance film typeapparatus, the scanning driving section 9 of FIGS. 4A and 4B may be acircuit for AC driving similarly as in the foregoing description or maybe a circuit for DC driving by application of a DC voltage. Whicheverdriving method is adopted for the scanning driving section 9, if adetection object such as a finger or a stylus pen touches the detectionface, then an electric characteristic such as a voltage of the drivingelectrodes DE at the touching position is transmitted to a sensor lineSL through a sensor switch not shown. Though not particularly shown,such sensor switches are disposed substantially in a matrix on anarrangement face parallel to the detection face. The sensor switches arepressure switches which are individually disposed at crossing pointsbetween the driving electrodes DE and the sensor lines SL andshort-circuit them only when pressing force by touching is applied butcancel the short-circuiting when the pressing force is removed.

If the sensor switch is switched on at least at one of the crossingpoints of the driving electrodes DE and the sensor lines SL, then anelectric variation occurs with the corresponding sensor line SL at acertain point of time which corresponds to a detection positioncoordinate in the y direction. The touch detection section 8 can detectthe touched position of the detection face from the sensor line SL withwhich the electric variation occurs, that is, the detection positioncoordinate in the x direction, and the time of occurrence of theelectric variation, that is, the detection position coordinate in the ydirection.

Where the present invention is applied to an optical type apparatus,though not particularly shown, the scanning driving section 9 of FIG. 4Acontrols, for example, a detection driving voltage for controlling atransistor which reads out accumulated charge of a photodiode in thelight reception circuit. In other words, the scanning driving section 9in this instance is a DC-driven scanning circuit by DC voltageapplication.

Light from a light source not shown is emitted externally from thedetection face and is reflected by a detection object and returned tothe detection face. The reflected light enters the touch detectionapparatus through the detection face and is received by a photodiode orphotodiodes. A large number of such photodiodes are formed, for example,in a matrix on an arrangement plane parallel to the detection face.Therefore, by several photodiodes corresponding to the position ofdetection object, charge accumulation is carried out by reception of thereflected light. The scanning driving section 9 repeats operation ofapplying a detection driving voltage and shift operation, and byapplication of the detection driving voltage, output permission of thephotodiode of the light reception circuit is issued and an electricvariation occurs with the sensor lines SL. Consequently, an electricvariation of the sensor lines SL occurs at a certain point of time whichcorresponds to the detection position coordinate in the y direction. Thetouch detection section 8 can detect the touched position in thedetection face from the sensor lines SL with which an electric variationoccurs, that is, the coordinates of the detection positions in the xdirection, and the time of occurrence, that is, the detection positioncoordinates in the y direction.

From the foregoing, the present invention can be applied widely to atouch detection apparatus which outputs detection signals using thesensor lines SL in the form of parallel stripes arranged long in acertain fixed direction and a display apparatus having a function forthe touch detection. This system can be applied irrespective of thedetection type such as, the capacitance type, resistance film type oroptical type.

In touch detection of this system, by scanning detection drivingvoltages in a direction different from the arrangement direction of thesensor lines SL, an x coordinate and a y coordinate of a detectionposition can be specified from an address of a sensor line and timeinformation on and at which an output is obtained.

Also in the resistance film type apparatus and the optical typeapparatus described above, similarly as in the capacitance typeapparatus described hereinabove, since the scanning driving section 9carries out scanning in accordance with a predetermined algorithmincluding jump shift operation, the advantage that presence or absenceof a detection object can be decided at an earlier stage than that inthe alternative case of sequential scanning. As a result, the latencycan be improved without raising the detection driving frequency.

4. Applications to Electronic Apparatus

Now, applications of the display apparatus described hereinabove inconnection with the second embodiment and the modifications describedabove are described with reference to FIGS. 20A and 20B to 23A and 23B.The display apparatus according to the second embodiment and themodifications described hereinabove can be applied to electronicapparatus in various fields such as a television apparatus, a digitalcamera, a notebook type personal computer, a portable terminal apparatussuch as a portable telephone set and a video camera. In other words, theapparatus according to the second embodiment and the modificationsdescribed above can be applied to electronic apparatus in various fieldswherein an image signal inputted from the outside or an image signalgenerated in the inside is displayed as an image. Here, principalelectronic apparatus are described.

FIGS. 20A and 20B show a digital camera to which the present inventionis applied, and particularly FIG. 20A is a front elevational view andFIG. 208 is a rear elevational view.

Referring to FIGS. 20A and 20B, the digital camera 310 shown includes animage pickup lens in a protective cover 314, a flash light emittingsection 311, a display section 313, a control switch, a menu switch, ashutter 312 and so forth. The digital camera 310 is produced using thedisplay apparatus having the touch sensor function described hereinabovein connection with the second embodiment and the modifications as thedisplay section 313.

FIG. 21 shows a notebook type personal computer to which an embodimentof the present invention is applied.

Referring to FIG. 21, the notebook type personal computer 340 shownincludes a keyboard 342 provided on a body 341 for being operated toinput characters and so forth, a display section 343 provided on a bodycover for displaying an image. The notebook type personal computer 340is produced using the display apparatus having the touch sensor functiondescribed hereinabove in connection with the second embodiment and themodifications as the display section 343.

FIG. 22 shows a video camera to which an embodiment of the presentinvention is applied.

Referring to FIG. 22, the video camera 320 shown includes a body section321, and a lens 322 for picking up an image of an image pickup object, astart/stop switch 323 for image pickup, a monitor 324 and so forthprovided on a face of the body section 321 which is directed forwardly.The video camera 320 is produced using the display apparatus having thetouch sensor function described hereinabove in connection with thesecond embodiment and the modifications as the monitor 324.

FIGS. 23A and 23B show a portable terminal apparatus to which anembodiment of the present invention is applied, and particularly FIG.23A shows the portable terminal apparatus in an open state and FIG. 23Bshows the portable terminal apparatus in a closed state.

Referring to FIGS. 23A and 23B, the portable terminal apparatus 330includes an upper side housing 331, a lower side housing 332, aconnection section 333 in the form of a hinge section, a display section334, a sub display section 335, a picture light 336, a camera 337 and soforth. The portable terminal apparatus 330 is produced using the displayapparatus with the touch sensor described hereinabove in connection withthe second embodiment and the modifications as the display section 334or the sub display section 335.

It is to be noted that also it is possible to build the touch detectionapparatus according to the first embodiment which has no displayfunction in various electronic apparatus similarly to the applicationsdescribed hereinabove.

In summary, according the embodiments of the present invention,modifications of the embodiments and applications of the embodiments andthe modifications, a touch detection apparatus, a display apparatus andan electronic apparatus which are improved in latency upon operation bytouch can be provided.

The present application contains subject matter related to thatdisclosed in Japanese Priority Patent Application JP 2009-120614 filedin the Japan Patent Office on May 19, 2009, and Japanese Priority PatentApplication JP 2010-063024 filed in the Japan Patent Office on Mar. 18,2010, the entire contents of which are hereby incorporated by reference.

While preferred embodiments of the present invention have been describedusing specific terms, such description is for illustrative purposesonly, and it is to be understood that changes and variations may be madewithout departing from the spirit or scope of the following claims.

The invention claimed is:
 1. A display apparatus, comprising: a displayface; a display function layer adapted to display image data on thedisplay face in response to an input image signal; a plurality ofdriving electrodes disposed separately in one direction; a detectionscanning control section configured to apply a detection driving voltagesimultaneously to some of the plurality of driving electrodes and carryout detection scanning while shifting application of the detectiondriving voltage in the one direction and control the detection scanningsuch that jump shifts are performed at a pitch of two times or more ofan arrangement pitch of the driving electrodes; a plurality of sensorlines disposed separately in a direction different from the onedirection and responding to touch or proximity of a detection objectwith or to the display face to exhibit an electric variation, wherein inthe jump shifts, the detection scanning control section applies thedetection driving voltage to some of the plurality of drivingelectrodes, the detection scanning control section is capable ofcarrying out a sequential shift in which an application target of thedetection driving voltage is sequentially shifted in the one directionat the arrangement pitch of the driving electrodes, and the detectionscanning control section alternately performs the sequential shift apredetermined number of times and the jump shift a single time.
 2. Thedisplay apparatus according to claim 1, further comprising a displayscanning control section configured to control display driving scanning,wherein the detection scanning control section carries out, within aperiod of the display driving scanning for N screens by the displayscanning control section, the detection driving scanning for N+1pictures or more.
 3. The display apparatus according to claim 2, whereinthe detection driving scanning by the detection scanning control sectionand the display driving scanning by the display scanning control sectionare carried out in synchronism with each other for the plurality ofdriving electrodes.
 4. The display apparatus according to claim 3,further comprising a plurality of separated pixel electrodes and adaptedto apply a display voltage to the display function layer for each pixelwhen the image signal is supplied, wherein the plurality of drivingelectrodes function also as a plurality of display driving electrodeswhich are disposed in a pitch equal to a natural number of times a pixelpitch defined by the display function layer and to which a displaydriving voltage for applying a reference to the display voltage upondisplay variation by the display function layer successively in the onedirection from the display scanning control section.
 5. The displayapparatus according to claim 4, wherein the detection scanning controlsection carries out application of the detection driving voltage at thesame time to m ones of the driving electrodes, m being equal to orgreater than two.
 6. The display apparatus according to claim 5,wherein: the plurality of sensor lines are disposed on the display faceside of the display function layer; the plurality of driving electrodesare disposed on the side opposite to that of the display face of thedisplay function layer; and the plurality of pixel electrodes aredisposed between the display function layer and the plurality of drivingelectrodes.
 7. The display apparatus according to claim 6, wherein thedisplay function layer is a liquid crystal layer.
 8. The displayapparatus according to claim 7, wherein the detection scanning controlsection functions also as the display scanning control sectionconfigured to supply and control the display driving voltage.
 9. Thedisplay apparatus according to claim 1, wherein the detection scanningcontrol section carries out application of the detection driving voltageat the same time to m ones of the driving electrodes, m being equal toor greater than two.
 10. The display apparatus according to claim 1,wherein the plurality of sensor lines are disposed on the display faceside of the display function layer; the plurality of driving electrodesare disposed on the side opposite to that of the display face of thedisplay function layer, and a plurality of pixel electrodescorresponding to each pixel and apply a display voltage for which apotential of a corresponding driving electrode is used as a reference tothe display function layer for each pixel when the image signal issupplied are disposed between the display function layer and theplurality of driving electrodes.
 11. The display apparatus according toclaim 1, wherein the display function layer is a liquid crystal layer.12. The display apparatus according to claim 1, wherein the detectionscanning control section controls the detection driving scanning suchthat the application object of the detection driving voltage is changedin order in the one direction among the plurality of driving electrodesdisposed separately in the one direction.
 13. The display apparatusaccording to claim 1, wherein, where a period from a current shift to anext shift is determined as one cycle, the detection scanning controlsection periodically executes and controls driving halting of one ormore cycles in which application of the detection driving voltage is notcarried out.
 14. The display apparatus according to claim 13, furthercomprising a touch detection section configured to generate a detectionsignal from the electrical variation appearing on the sensor lines,wherein the touch detection section includes a noise removing sectionconfigured to detect, within a period of the driving halting, a noiselevel from the potential level of the sensor lines on which theelectrical variation from which the detection signal is generated is notsuperposed and carrying out noise removal.
 15. The display apparatusaccording to claim 1, wherein, where the shift operation is carried outby P times the driving electrode pitch, P being equal to or greater than1, the detection scanning control section randomly controls the value ofP.
 16. The display apparatus according to claim 1, wherein each of thesensor lines is coupled to each of the driving electrodes through acapacitance, and a peak value of a potential variation which appears,when the detection driving voltage is applied to any of the drivingelectrodes, with one of the sensor lines which corresponds to thedriving electrode differs between one or more ones of the sensor lineswhich correspond to contact or proximity of the detection object and theother sensor lines.
 17. A touch detection apparatus, comprising: adetection face; a plurality of driving electrodes disposed separately inone direction; a detection scanning control section configured to applya detection driving voltage simultaneously to some of the plurality ofdriving electrodes and carry out detection driving scanning whileshifting application of the detection driving voltage in the onedirection and control the detection driving scanning such that jumpshifts are performed at a pitch of two times or more of an arrangementpitch of the driving electrodes; and a plurality of sensor linesdisposed separately in a direction different from the one direction andadapted to exhibit, if a detection object is brought into touch with orproximity to the detection face while the detection driving scanning isbeing carried out by the detection scanning control section, electricvariation in response to the touch or the proximity, wherein in the jumpshifts, the detection scanning control section applies the detectiondriving voltage to some of the plurality of driving electrodes, thedetection scanning control section is capable of carrying out asequential shift in which an application target of the detection drivingvoltage is sequentially shifted in the one direction at the arrangementpitch of the driving electrodes, and the detection scanning controlsection alternately performs the sequential shift a predetermined numberof times and the jump shift a single time.